for what its worth on big jobs not just belts we often get one of the techs to take a vehicle home overnight to make sure it has no issues on longer drives that you cant dedicate time to during work hours this goes for engine work headspistonsrodsturboetc tranny work replacementrebuild and complicated electrical work its not a joy ride it has also saved comebacks where the noiseissue popped up overnight and was dealt with before the customer got their car back and had to deal with it yet again